A series coupled fused-silica open tubular columns of a chiral and an achiral stationary phase were used to achieve the enantiomeric separation of a-phenylethylamine, o,m,p-methyl-and o,m,p-methoxy-a-phenylethylamine. A simplified equation describing the retention values of series coupled columns was derived, which relates the capacity factors of series coupled columns to the capacity factor of individual columns, their lengths, inlet and outlet pressure. Very good agreement was obtained both between calculated values by this equation and those by Krupcik’s equation and between values measured experimentally and calculated theoretically. By means of this simplified equation a computer program was developed in locating the operating range of optimum amin, enantiomeric separation of all a-phenylethylamine and its derivatives were achieved in a single run. A series coupled fused-silica open tubular columns of a chiral and an achiral stationary phase were used to achieve the enantiomeric separation of a-phenylethylamine, o, m, p-methyl-and o, m, p-methoxy-a-phenylethylamine. A simplified equation describing the retention values ​​of series coupled columns was derived, which relates the capacity factors of series coupling columns to the capacity factor of individual columns, their lengths, inlet and outlet pressure. equation and those by Krupcik’s equation and between values ​​of experimentally and calculated theoretically. By means of this simplified equation a computer program was developed in locating the operating range of optimum amin, enantiomeric separation of all a-phenylethylamine and its derivatives were achieved in a single run.